<template>
  <view>
    <view class="scroll-view-container">
      <!-- 左侧的滑动区域 -->
      <scroll-view scroll-y="true" class="left-scroll-view" :style="{height: wh +'px'}">
        <block v-for="(item,i) in cateList" :key="i">
          <!-- active -->
          <view :class="[' left-scroll-item', i === active? 'active':' ' ]" @click="activeChanged(i)">{{item.cat_name}}</view>
        </block>
      </scroll-view>
      <!-- 右侧的滑动区域 -->
      <scroll-view scroll-y="true" :style="{height: wh +'px'}" :scroll-top="scrollTop">
        <block v-for="(item2,i2) in cateLevel2" :key='i2'>
          <!-- 耳机分类标题 -->
            <view class="cate-lv2-title">/ {{item2.cat_name}} /</view>
            <!-- 当前二级分类下的三级分类列表 -->
            <view class="cate-lv3-list">
              <!-- 三级项 -->
               <view class="cate-lv3-item" v-for="(item3,i3) in item2.children" :key='i3' @click="gotoGoodsList(item3)">
                 <!-- 三级图片 -->
                 <image :src="item3.cat_icon" ></image>
                 <!-- 三级文本 -->
                 <text>{{item3.cat_name}}</text>
               </view>
            </view>
        </block>
      </scroll-view>
    </view>
  </view>
</template>

<script>
  export default {
    data() {
      return {
        // 屏幕高度
        wh: 0,
        //左侧数据
        cateList: [],
        active: 0,
        //二级分类列表
        cateLevel2:[],
        scrollTop:0,
      };
    },
    onLoad() {
      const sysInfo = uni.getSystemInfoSync();
      this.wh = sysInfo.windowHeight;
      this.getCateList();
    },
    methods: {
      activeChanged(i){
        this.active=i;
        this.cateLevel2= this.cateList[i].children;
       this.scrollTop= this.scrollTop===0 ? 1 :0;
      },
      async getCateList() {
        const {
          data: res
        } = await uni.$http.get('/api/public/v1/categories')
        if (res.meta.status != 200) return uni.$showMsg()
        
        this.cateList = res.message;
        this.cateLevel2=res.message[0].children;
      },
        //跳转到商品页面
      gotoGoodsList(item){
        uni.navigateTo({
          url : '/subpkg/goods_list/goods_list?cid='+item.cat_id
        })
      }
    }
  }
</script>

<style lang="scss">
  .scroll-view-container {
    display: flex;

    .left-scroll-view {
      width: 120px;

      .left-scroll-item {
        background-color: #F7F7F7;
        line-height: 60px;
        text-align: center;
        font-size: 12px;

        &.active {
          background-color: #fff;
          position: relative;

          &::before {
            content: ' ';
            display: block;
            width: 3px;
            height: 30px;
            background-color: #C00000;
            position: absolute;
            top: 50%;
            left: 0;
            transform: translateY(-50%);
          }
        }
      }
    }
   
  
  }
  .cate-lv2-title{
    font-size: 12px;
    padding: 15px 0;
    text-align: center;
    font-weight: bold;
  }
  .cate-lv3-list{
    display: flex;
    flex-wrap: wrap;
    .cate-lv3-item{
      width: 33.33%;
      display: flex;
      flex-direction: column;
      justify-content: center;
      align-items: center;
      margin-bottom: 10px;
      image{
        width: 60px;
        height: 60px;
      }
      text{
        font-size: 12px;
      }
    }
  }
</style>
